Clamps are structures designed for pinching host tissue. They are compound structures, usually formed by some form of sucker in conjunction with internal sclerites or bars for strength. They are common structures on the opisthaptor of monogeneans.
The opisthaptor of Octomacrum is fitted with eight large clamps. Note the complex arrangement of sclerites within each clamp.
Nudacirraxine makes use of a large number of small clamps.
